This invention relates to an electronic cooking range having a door interlocking switch circuit for controlling a microwave generation device of the electronic cooking range safely, the interlocking switch circuit of said electronic range enabling an increase in efficiency of examination time, constituting switches for opening and closing mechanism of doors with low capacity switches, thereby improving safety.
FIG. 9 is a perspective view of the electronic cooking range 15, wherein 10 is a door, 16 is a microwave generation device provided therein, 17 is a cooling fan, and 18 is a power transformer. FIG. 10 shows a main part of a section taken on line 10--10 in FIG. 9 and indicates an interlocking switch circuit mechanism at the inside of the door 10. Generally, the interlock switch circuit is provided with three switches, a monitor switch 1 at connected point b, a primary switch 2 at connected point a, and a secondary switch 3 at connected point a.
In this case, the monitor switch 1 among them a switch which informs a CPU (central processing unit) of a detection of the opening or closing of the door 10 and is adapted to operate prior to operations of the primary switch 2 and the secondary switch 3. In other words, the monitor switch 1 is constituted to open before the primary switch 2 and the secondary switch 3 open when the door 10 is closed, and to close after said primary switch 2 and the secondary switch 3 close when the door 10 is opened. The primary and the secondary switches 2 and 3 are, respectively, safety switches on power supply line and detect the opening and closing of the door 10 through an inner and circuit. Thus, the interlocking switch circuit of the electronic range is opened or closed mechanically in a certain order when the door of the electronic range opens or closes for maintaining safety at the time of its use.
In FIG. 10, the operation thereof is as follows.
When the door is closed, a hook link 4 urges a button 1A through an arm 11 of the monitor switch 1 by a lower top end 4B thereof, whereby the monitor switch 1 is on (the door opens) at first. Then, when the button 2A is urged by the top end 4 of the hook link 4, the primary switch 2 is on (the door closes) whereby the switch lever 12 rotates to urge a button 3A, thereby being on (the door is closed) the secondary switch 3. Reversely, when the door 10 is opened, the monitor switch 1 is on (the door opens) last after primary switch 2 and secondary switch 3 are off (the door opens). Thus, even if the switch does not work, the electronic range is separated from DC current completely to maintain safety. Further, 6 is a door-open lever, 7 is a door-open button and 8 is a spring.
FIG. 7 is a block diagram which shows a constitution of the inner circuit of the electronic range 15, 21 is a microcomputer, and 22 is a ROM (read only memory) of the microcomputer 21 wherein programs for control of the electronic range are stored. The numeral 23 is a timer, 24 is an operation part and 25 is an indicator which indicates several kinds of parameters such as heating times and the like.
FIG. 8 is a circuit drawing which shows the constitution of the microwave generation device 16 and a power supply circuit thereof, and 16a is a microwave generation part, 16b is a cathode heating coil for heating the cathode of the microwave generation part 16a, 16c is a high voltage generation coil for applying the high voltage to a plate of the microwave generation part 16a, and 31 is a fuse inserted into the power supply line.
Since the monitor switch 1, primary switch 2 and secondary switch 3 of the above conventional electronic range uses comparatively large current capacity switches respectively as much as at least 15 ampere, safety measures have to be taken. Particularly, in the electronic range for foreign countries, examinations of breaks, welding for said monitor switch 1, primary switch 2 and secondary switch 3 are obligated in order to satisfy the safety rules for sales such as the UL standards in the United States of America and the like at the time of shipment from factories.
This examination is performed respectively to said monitor switch 1, primary switch 2, and secondary switch 3 with two kinds of testers having a door hook form. The examination of the primary switch 2 is an examination for confirming that the microwave generation device 16 does not operate when the primary switch 2 is on by jig having said door-hook form. Further, the examination of the secondary switch 3 is an examination for confirming that the microwave generation device 16 does not operate when the secondary switch 3 is on by jig having said door-hook form. Still further, the examination of the monitor switch 1 is an examination for confirming that the power supply is burned out by operation of a break or fuse of the power with a jig having said door-hook form (the jig used in this case is a jig which makes the primary switch 2 on used at the time of examination of said primary switch 2 and a jig which makes the secondary switch 3 on and maintains the monitor switch 1 in closing state).
Since the conventional electronic range consists of the above, the examination at the time of the shipment from the factory must be performed by using not less than two kinds of jigs. Accordingly, it takes not only a long period of time for mounting or removing the jig, but also the examination process becomes complicated, including a decrease in safety and an increase in product cost.
In addition, since the switches which make up the interlocking switch circuit of the door use comparatively large current capacities such as 15A or so for driving the microwave generation device 16, a bold wire must be used, thereby causing a decrease in the safety of the electronic range due to proceeding of parts for large capacity switch mechanism and the corresponding increase in product costs.